Retractable firing pin



Jan, 13, 1959 D. P. GROVER RETRACTABLE FIRING PIN Filed Aug. 29, 1956 INVENTOR. Dunuld EETUVET 77 g JAM 9- a. a); Q-

Z, ,981 Patented Jan. 13, 1959 RETRACTABLE FIRING P N Donald P. Grover, Chicago, 111., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Army Application August 29, 1956, Serial No. 606,940

2 Claims. (Cl. 89-9135) My application relates to an automatic gun provided with transversely displaceable cartridge chambers and more particularly to a retractable firing pin therefor having a variable cartridge contacting position.

Conventional guns of this type are subject to misfire due to inability of the firing pins to contact the primers of those rounds which are seated deeply in the drums. Also, the useful lives of the firing pins are short due to excessive wear and breakage by the firing pin wiping across the bases of the cartridge during movement thereof to and from the firing station.

It is an object of my invention to provide a firing pin for such a gun having a variable cartridge contacting position.

Another object of my invention is to provide the gun with a floating firing device including a firing pin which is retractable out of contact with the chambered cartridges during movement thereof to and from the firing station of the gun.

Other aims and objects of my invention will appear from the following description and the accompanying drawing in which:

Fig. l is an elevational view in section of a portion of an automatic gun incorporating an embodiment of my invention with the actuator in a rearward position and the firing pin and lever in normal positions;

Fig. 2 is a view similar to Fig. l with the actuator in a forward position contacting the lever and thereby biasing the firing pin forward into contact with the primer of the cartridge; and

Fig. 3 is a view along line 3-3 of Fig. 2.

Shown in the figures is an automatic gun provided with a recoil unit 12 which includes a breech member 14 and a rotatable drum 16 which is provided with a plurality of chambers 18 for receiving cartridges 20 with such drum being disposed for successively carrying the cartridges to a firing station for discharge therein.

Since tolerances are allowed for machining and assembly of the gun and in the manufacture of the cartridges, the primers of the cartridges are disposed in drum 16 at depths within a predetermined range of values.

An actuator 22 is disposed for reciprocation through the forces produced by the discharge of the cartridges 29 in the firing station and for engagement with drum 16 for rotation thereof to successively move the chambers 18 to the firing station and to retain the chambers in the firing station when the actuator is in the forward battery position. A firing pin device 23 is mounted through breech member 14 for actuation into electrical contact with primer 21 of the cartridge 20 which is in the firing station. Firing pin device 23 includes a tubular housing 25 of material which will not conduct electricity, and a firing pin 26 and a striker 28 which are slidingly disposed in such housing. A sleeve 32 is slidingly mounted in housing 25 forwardly of striker 28 so as to be engaged therewith and a return spring 30 is compressed between the front end of a sleeve 32 and a bushing 54 mounted in the front end of housing 25 to bias Ld striker 28 rearwardly into engagement with a stop 24 fixed to the rear end of housing 25. Sleeve 32 includes a shoulder 34 which is engageable with a flange 36 on the rear end of firing pin 26 to limit the forward movement thereof respective to striker'28. The forward movement of firing pin 26, respective to housing 25, is limited by the engagement of a shoulder 52 on the firing pin with the rear end of bushing 54. A position spring 38 is disposed between firing pin 26 and striker 28 to press such firing pin forwardly relative to the striker and the tension of such spring is arranged to be less than that of return spring 30 so that sleeve 32 will remain pressed against striker 28 when the firig pin is in its farthest cartridge contacting position, wherein shoulder 34 engages flange 36, and so that the firing pin may be resiliently retracted within housing 25 through the contact of the forwardly projecting end of the firing pin with primer 21 of the cartridge 20 in the firing station when such primer is disposed within the predetermined range of values.

A lever 40 is pivotally mounted at 42 on breech member 14 and is biased rearwardly away therefrom by a spring 44. Lever 40 is engageable by an arm 46 resiliently mounted to actuator 22 when such actuator is in forward battery position and is arranged to be pivoted by such engagement against striker 28 for forward displacement thereof against return spring 30 with firing pin 26 being actuated by position spring 38 to the farthest cartridge contacting position thereof.

Firing pin 26 is connected through a spring contact 48 and cable 50 to a source of electric power for the dis charge.

' Thus, when actuator 22 is in forward battery position and drum 16 is held thereby to retain one of the chambers 18 in the firing station, striker 28 is pressed forwardly against the bias of return spring 36 by the engagement of arm 46 with lever 40 and firing pin 26 is biased forwardly by position spring 38 to contact the primer of the cartridge 20 disposed in the firing station. Firing pin 26 is slidingly disposed in firing pin device 23 for movement within a predetermined range of values, determined by the tolerances permitted in the manufacture of the gun and the cartridges 2%), to insure connection between such firing pin and primers 21 of all of the chambered cartridges and position spring 38 provides firm electrical contact between the engaged primers and such firing pin in all of the variable cartridge contacting positions thereof.

When the cartridge 20 in the firing station is fired by electric current passed thereto through firing pin 26 from cable 50, the force of the discharge moves actuator 22 rearwardly and thereby disengages arm 46 thereon from lever 40 which is then free to be pivoted rearwardly by spring 34. As lever 40 is pivoted rearwardly, return spring 30 biases striker 28 rearwardly to the normal position thereof and firing pin 26 is retracted from engagement with the primer of the discharged cartridge so as to be out of contact with the base of this cartridge when drum 18 is rotated during the remaining rearward travel of the actuator. When the following chamber 18 is rotated to the firing station by actuator 22, during the return thereof to forward battery position, arm 66 engages lever 40 to actuate striker 28 forwardly and thereby move firing pin 26 as hereinbefore explained into contact with the primer of the following cartridge 20 after such cartridge is moved to the firing station.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. In an automatic gun including a recoil unit with a U1 stop, a member in the recoil unit provided with chambers for inclosing cartridges with the primers thereof disposed in the chambers at depths within a predetermined range of values and a firing station for the chambers for discharge of the cartridges therein, and an actuator disposed for reciprocation with respect to the recoil unit to engage the member and convey the chambers to the firing station through the forces produced by the discharge, a firing device comprising a firing pin in the recoil unit, a striker in engagement with said firing pin, a sleeve inclosing said firing pin, a return spring engaging said sleeve to bias said striker towards the stop and said firing pin to a position spaced from the primers, a position spring disposed between said firing pin and said striker to .bias said firing pin towards electrical contact with primers disposed in the chambers at the greatest depth of the predetermined range and a lever pivoted and biased to a normal position on the recoil unit, said lever being disposed for engagement between said striker and the actuator.

2. A firing device as described in claim 1 with a spring member disposed on the actuator for engagement with said lever.

References Cited in the file of this patent UNITED STATES PATENTS 

